(a) Any member in service may retire upon written application to the board of trustees, provided that the member at the time of retirement: (1) has attained the age of 60 years and has at least ten years of creditable service, or (2) has at least 25 years of creditable service. The effective date of retirement will be the first of the month in which the application is received by the board of trustees; except that no retirement application will be effective earlier than the first of the month following the final month of the applicant's employment. Applications for retirement will not be accepted more than 180 days in advance of the effective date of retirement. Each employer shall certify to the board of trustees the date on which the employee's employment is or will be severed and that no agreement exists to allow the employee to return to service, including service as or for an independent contractor. Any return to employment or rendering of any paid service, including service as or for an independent contractor, for any employer during the calendar month of the effective date of retirement shall render the severance invalid and nullify the application for retirement.

(b) For purposes of this chapter, normal retirement age shall be 60 years of age if the member has at least ten years of creditable service or the age of the member on the date he or she attains 30 years of creditable service, whichever event comes first; provided, however, that the provisions of this subsection shall be subject to change by future legislation in order to comply with federal regulations. Except as provided under Article 3 of Chapter 1 of this chapter, a member's right to his or her retirement allowance is nonforfeitable upon attainment of normal retirement age.

(c) The benefits payable under Code Section 47-3-120 and under Code Section 47-3-122 shall be payable to the retired member for the remainder of his lifetime and shall be known as the maximum plan. Upon the death of the retired member, all monthly benefits shall cease as of the end of the month in which the retired member died. If the total monthly benefits paid at the time of the retired member's death are less than his accumulated contributions at the time of his retirement, the difference between the benefits paid and such accumulated contributions shall be refunded to the person who has been designated in writing by the retired member or to the retired member's estate, if no such person has been designated or if such designated person has predeceased the retired member. This subsection shall not apply when an optional allowance has been selected by the member under Code Section 47-3-121.

(d) The board of trustees is authorized to provide by rule or regulation for the payment of benefits to members or beneficiaries of the retirement system at a time and under circumstances not provided for in this chapter to the extent that such payment is required to maintain the Teachers Retirement System of Georgia as a "qualified retirement plan" for the purposes of federal income tax laws.